The present invention generally relates to jigs and methods for measuring laser power, and more particularly to a jig and a method for measuring the power of a laser beam which is emitted from an optical head of an optical disk unit.
In optical disk units, the power of the laser beam emitted from the optical head affects the signal-to-noise (S/N) ratio when recording and reproducing information on and from an optical disk. For this reason, the laser power is one of the important items to be managed during an inspection process which is carried out when the optical disk unit is completed and during a maintenance operation which is carried out after completion of the optical disk unit. Various adjustments are made according to the needs based on the results of the laser power measurement.
The optical head includes a laser diode, a plurality of optical elements and an objective lens. The laser beam which is emitted from the laser diode of the optical head passes through the plurality of optical elements before being outputted via the objective lens, and thus, the laser beam becomes attenuated after passing through the optical elements. In order to measure the laser power so as to appropriately adjust the laser power, it is necessary to detect the laser beam at the position of the surface of the optical disk which is loaded into the optical disk unit and measure the laser power of the laser beam which is outputted via the objective lens. When actually making this laser power measurement, it is desirable that the measurement can be made with a high operational efficiency.
Conventionally, the laser power is measured using a sensor 1 shown in FIG. 1 which is on the market. First, an outer cover 3 of an optical disk unit 2 is removed, and a plurality of screws are removed to remove a printed circuit assembly 4 which is provided on the upper part of the optical disk unit 2. As a result, the inside of the optical disk unit 2 is exposed.
In this state, the sensor 1 which is coupled to a power meter 5 is arranged above an objective lens 7 of an optical head 6 so as to measure the laser power. For this reason, there are problems in that it takes time to prepare for the laser power measurement, and that it is necessary to reassemble the optical disk unit 2 back into its original state after the laser power measurement. In other words, it is difficult to make the laser power measurement with a high operational efficiency.